Electrical Bio-Impedance based non-invasive method for the Central Aortic blood pressure waveform estimation

Non-invasive and safe method for estimation of the Central Aortic Pressure (CAP) waveform is presented. It is based on the measurement of Electrical Bio-Impedance (EBI) on radial artery. Reconstruction of the CAP curve from the EBI data is provided by an introduced spectral domain transfer function (TF). The TF estimation algorithm and the Augmentation Index (AI) evaluation method are described. Proposed approach is less dependent on the operator and more convenient than traditional tonometry based method. It allows continuous and long term monitoring of the AI and CAP variations. Feasibility and accuracy of the technique was evaluated in clinical surroundings by comparing invasively measured CAP and AI data with non-invasive EBI based estimates. Clinical experiments were conducted in the Heart Centre of the East-Tallinn Central Hospital during scheduled coronary angiography. Age of the patients varied randomly between 43 and 80.